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Category: neuroscience – Page 362

Toward a Proprioceptive Neural Interface that Mimics Natural Cortical Activity

The dramatic advances in efferent neural interfaces over the past decade are remarkable, with cortical signals used to allow paralyzed patients to control the movement of a prosthetic limb or even their own hand. However, this success has thrown into relief, the relative lack of progress in our ability to restore somatosensation to these same patients. Somatosensation, including proprioception, the sense of limb position and movement, plays a crucial role in even basic motor tasks like reaching and walking. Its loss results in crippling deficits. Historical work dating back decades and even centuries has demonstrated that modality-specific sensations can be elicited by activating the central nervous system electrically. Recent work has focused on the challenge of refining these sensations by stimulating the somatosensory cortex (S1) directly. Animals are able to detect particular patterns of stimulation and even associate those patterns with particular sensory cues. Most of this work has involved areas of the somatosensory cortex that mediate the sense of touch. Very little corresponding work has been done for proprioception. Here we describe the effort to develop afferent neural interfaces through spatiotemporally precise intracortical microstimulation (ICMS). We review what is known of the cortical representation of proprioception, and describe recent work in our lab that demonstrates for the first time, that sensations like those of natural proprioception may be evoked by ICMS in S1. These preliminary findings are an important first step to the development of an afferent cortical interface to restore proprioception.

Keywords: Intracortical microstimulation (ICMS); Prosthesis; Somatosensation; Somatosensory cortex.

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Microglia rescue neurons from aggregate-induced neuronal dysfunction and death through tunneling nanotubes

In a recent study published in Neuron, researchers discovered that microglia, the brain’s immune cells, use tunneling nanotubes…

Scheiblich et al. uncover a novel mechanism by which microglia use tunneling nanotubes to connect with α-syn-or tau-burdened neurons, enabling transfer of these proteins to microglia for clearance. Microglia donate mitochondria to restore neuronal health, shedding light on new therapeutic strategies for neurodegenerative diseases.

New Technology to Control the Brain Using Magnetic Fields Developed

Nano-MIND Technology for Wireless Control of Brain Circuits with Potential to Modulate Emotions, Social Behaviors, and Appetite.

Researchers at the Center for Nanomedicine within the Institute for Basic Science (IBS) and Yonsei University in South Korea have unveiled a groundbreaking technology that can manipulate specific regions of the brain using magnetic fields, potentially unlocking the secrets of high-level brain functions such as cognition, emotion, and motivation. The team has developed the world’s first Nano-MIND (Magnetogenetic Interface for NeuroDynamics) technology, which allows for wireless, remote, and precise modulation of specific deep brain neural circuits using magnetism.

The human brain contains over 100 billion neurons interconnected in a complex network. Controlling the neural circuits is crucial for understanding higher brain functions like cognition, emotion, and social behavior, as well as identifying the causes of various brain disorders. Novel technology to control brain functions also has implications for advancing brain-computer interfaces (BCIs), such as those being developed by Neuralink, which aim to enable control of external devices through thought alone.

While magnetic fields have long been used in medical imaging due to their safety and ability to penetrate biological tissue, precisely controlling brain circuits with magnetic fields has been a significant challenge for scientists.

Common Sedative Could Break Consciousness by Tipping Your Brain Into Chaos

A loss of controlled inhibition of overly excited brain cells might explain how a common knock-out anesthesia drug works.

A new animal study led by researchers from the Massachusetts Institute of Technology (MIT) has found that propofol, a sedative used to safely lull people into unconsciousness for medical procedures, disrupts the brain’s normal ability to regain control of highly excitable neurons.

“The brain has to operate on this knife’s edge between excitability and chaos,” explains MIT neuroscientist and senior study author Earl Miller.

In vivo magnetogenetics for cell-type-specific targeting and modulation of brain circuits

Minimally invasive cellular-level target-specific neuromodulation is needed to decipher brain function and neural circuitry. Here nano-magnetogenetics using magnetic force actuating nanoparticles has been reported, enabling wireless and remote stimulation of targeted deep brain neurons in freely behaving animals.

“Eureka Moments” Shed Light on Consciousness

For generations, researchers have been pondering the question of how and where consciousness is formed in the brain.

Professor Ekrem Dere from Ruhr University Bochum, Germany, proposes a new approach to researching conscious cognitive information processing. He advocates defining phases of conscious cognitive processes on the basis of behavioral observations and learning curves.

The Clinical, Philosophical, Evolutionary and Mathematical Machinery of Consciousness: An Analytic Dissection of the Field Theories and a Consilience of Ideas

The Cartesian model of mind-body dualism concurs with religious traditions. However, science has supplanted this idea with an energy-matter theory of consciousness, where matter is equivalent to the body and energy replaces the mind or soul. This equivalency is analogous to the concept of the interchange of mass and energy as expressed by Einstein’s famous equation [Formula: see text]. Immanuel Kant, in his Critique of Pure Reason, provided the intellectual and theoretical framework for a theory of mind or consciousness. Any theory of consciousness must include the fact that a conscious entity, as far as is known, is a wet biological medium (the brain), of stupendously high entropy. This organ or entity generates a field that must account for the “binding problem”, which we will define. This proposed field, the conscious electro-magnetic information (CEMI) field, also has physical properties, which we will outline. We will also demonstrate the seamless transition of the Kantian philosophy of the a priori conception of space and time, the organs of perception and conception, into the CEMI field of consciousness. We will explore the concept of the CEMI field and its neurophysiological correlates, and in particular, synchronous and coherent gamma oscillations of various neuronal ensembles, as in William J Freeman’s experiments in the early 1970s with olfactory perception in rabbits. The expansion of the temporo-parietal-occipital (TPO) cortex in hominid evolution epitomizes metaphorical and abstract thinking. This area of the cortex, with synchronous thalamo-cortical oscillations has the best fit for a minimal neural correlate of consciousness. Our field theory shifts consciousness from an abstract idea to a tangible energy with defined properties and a mathematical framework. Even further, it is not a coincidence that the cerebral cortex is very thin with respect to the diameter of the brain. This is in keeping with its fantastically high entropy, as we see in the event horizon of a black hole and the conformal field theory/anti-de Sitter (CFT/ADS) holographic model of the universe. We adumbrate the uniqueness of consciousness of an advanced biological system such as the human brain and draw insight from Avicenna’s gendanken, floating man thought experiment. The multi-system high volume afferentation of a biological wet system honed after millions of years of evolution, its high entropy, and the CEMI field variation inducing currents in motor output pathways are proposed to spark the seeds of consciousness. We will also review Karl Friston’s free energy principle, the concept of belief-update in a Bayesian inference framework, the minimization of the divergence of prior and posterior probability distributions, and the entropy of the brain. We will streamline these highly technical papers, which view consciousness as a minimization principle akin to Hilbert’s action in deriving Einstein’s field equation or Feynman’s sum of histories in quantum mechanics. Consciousness here is interpreted as flow of probability densities on a Riemmanian manifold, where the gradient of ascent on this manifold across contour lines determines the magnitude of perception or the degree of update of the belief-system in a Bayesian inference model. Finally, the science of consciousness has transcended metaphysics and its study is now rooted in the latest advances of neurophysiology, neuro-radiology under the aegis of mathematics.

Keywords: anatomy & physiology; brain anatomy; disorders of consciousness; philosophy.

Copyright © 2020, Kesserwani et al.

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